Pembrolizumab-induced dual endocrine disruption: A case report

Immunotherapy is an increasingly used treatment for different types of cancer. The most widely used are cytotoxic T-lymphocyte antigen 4 (CTLA-4) inhibitors, PD-1 ligand (PD-L1) inhibitors and PD-1 receptor inhibitors. All of them can produce endocrine autoimmune side effects in multiple organs. The most frequent are thyroid disorders and hypophysitis although, less frequently, they can also cause autoimmune adrenalitis and autoimmune diabetes. Thyroid involvement is usually transient but can become chronic in the form of hypothyroidism in more than 50% of cases. Diabetes is due to autoimmune destruction of pancreatic β-cells, in many cases abrupt and irreversible. The 2 entities occur more frequently with PD-1 or PD-L1 inhibitors. This is the case of a patient with cutaneous melanoma on pembrolizumab who simultaneously developed thyroiditis and fulminant autoimmune diabetes.